# NTSB WPR21LA072: Navion Navion A, N4106K, Livermore, CA, December 21, 2020 - Type: NTSB accident investigation - Classification: Accident · No injuries · Class 3 · Limited · Final report - Date: December 21, 2020, 15:25 local (23:25 UTC) - Place: Livermore, CA · Airport environment - Coordinates: 37.693052, -121.81164 - Nearby events: https://openairdocs.org/map.md?lat=37.6931&lon=-121.8116&mi=10 - Phase of flight: [Approach](https://openairdocs.org/ntsb-phases/500) (OpenAirDocs' grouping) - Defining event: [Approach-VFR pattern crosswind: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Western Pacific Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 102448 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR21LA072 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/102448/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=102448 - Page: https://openairdocs.org/ntsb/WPR21LA072 ## Probable cause The improper installation of the gascolator fuel inlet line and hose clamp connection, which resulted in the total loss of engine power. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Navion NAVION A, 1 case](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=6150104), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md) - [Fuel system: fuel distribution](https://openairdocs.org/ntsb-findings/01022820): Aircraft › Aircraft systems · Incorrect service/maintenance (probable cause); cases with it: [Navion NAVION A, 1 case](https://openairdocs.org/ntsb-findings/01022820/cases.md?model=6150104), [All aircraft, 141 cases](https://openairdocs.org/ntsb-findings/01022820/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Approach-VFR pattern crosswind: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Navion NAVION A, 3 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=6150104), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) ## Analysis The airplane had an annual inspection and new wingtip fuel tanks installed about 6 months before the accident. The accident flight was the first flight since the maintenance. The pilot completed a normal runup inspection and the engine developed full power during takeoff. However, at an altitude of approximately 500 ft above ground level (agl), as the pilot turned onto the crosswind leg of the traffic pattern, the engine began to surge and lose power. As the pilot reduced the power for landing on the downwind leg, the engine lost total power. When the pilot realized the airplane would not make it to the runway, he prepared for a landing on the grass area parallel to the runway. The airplane touched down and the left wing impacted concrete blocks. A postaccident examination of the engine revealed a leaking gascolator fuel inlet line caused by a loose hose clamp connection on the fuel line from the fuel selector to the gascolator. The loose connection allowed a large amount of air to be introduced into the fuel line going to the engine and fuel pumps, which caused the engine to surge and eventually lose power. The examination also revealed several maintenance discrepancies. The leaking fuel inlet line was made of rubber instead of aluminum tubing, and the fuel selector's connection was improper. Additionally, the wingtip fuel tank installation revealed several inconsistencies with the installation, such as loose clamps and improper hardware installed. These discrepancies were an indication of improper recent maintenance. ## Factual narrative On December 21, 2020, at 1525 Pacific standard time, a Navion A, N4106K, was substantially damaged when it was involved in an accident near Livermore, California. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The airplane had new wingtip fuel tanks installed in July 2020, and an annual inspection was completed at the same time. The accident flight was the first flight since the fuel tank installation. The pilot departed from runway 7R at Livermore Municipal Airport (LVK), after a normal runup inspection. The engine developed full power during takeoff; however, at an altitude of approximately 500 ft above ground level (agl), as the pilot turned onto the crosswind leg of the traffic pattern, the engine began to surge and lose power. As the pilot reduced the power for landing on the downwind leg, the engine lost total power. When the pilot realized the airplane would not make it to the runway, he prepared for a landing on the grass area parallel to the runway. The airplane touched down and the left wing impacted concrete blocks. A postaccident examination of the engine revealed a leaking gascolator fuel inlet line and a loose hose clamp connection on the fuel line from the fuel selector to the gascolator. The line was made of rubber instead of aluminum tubing, and the fuel selector's connection was improper. Additionally, the wingtip fuel tank installation revealed several inconsistencies with the installation, such as loose clamps and improper hardware installed. ## Aircraft - Registration: [N4106K](https://openairdocs.org/aircraft/N4106K), registered now, S/N NAV-4-1106 (OpenAirDocs) - Reported make and model: NAVION Navion A - Registry model: [Navion NAVION A](https://openairdocs.org/model/navion-navion-a) (registry code 6150104) (OpenAirDocs) - Registry engine: [Continental E185 series](https://openairdocs.org/engine/continental-e185-series) (registry code 17014, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: NAV-4-1106 - Airframe hours: 5277 - Engines: Continental Motors IO-520-BB3B 205 horsepower reciprocating - Damage: Substantial damage - Flight: Flight test, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 28, 2020, 0.2 hours before - Destination: Same as departure - Airport: LVK, Livermore Muni, runway 25R, 5,253 × 100 ft, asphalt - Equipment: ADS-B, Auto-pilot ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 82; injuries: none; airline transport; airplane ratings: multi-engine sea, single-engine land, multi-engine land, single-engine sea; instrument ratings: airplane; medical: basicmed; last flight review August 8, 2019; seat: left; restraint: lap only; flight hours: 17,341 total, 10 in this make and model, 7,611 as pilot in command, 1 in the last 90 days, 1 in the last 30 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: variable at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 61 °F, dew point 39 °F - Altimeter: 30.02 inHg - Observed at: KLVK - METAR: KLVK 212253Z VRB03KT 10SM CLR 16/04 A3002 RMK AO2 SLP165 T01560039 ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20201221019079A](https://openairdocs.org/incident/20201221019079A), Dec 21, 2020: Navion NAVION A, Livermore, CA, Destroyed. A Navion A N4106K took off from Livermore, CA. Airport for test flight and on downwind leg returning to runway, engine lost power, pilot then turned base,… ## Docket (6 files) The files NTSB released with the investigation on August 23, 2022, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=102448. 45.4 MB in all. - Pilot/operator aircraft accident report, NTSB form 6120.1 (item 1, PDF, 10 pages, 3.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13194371&FileExtension=pdf&FileName=WPR21LA072%206120_Redacted-Rel.pdf - Record of conversation FAA (NTSB) (item 2, PDF, 1 page, 94 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14256303&FileExtension=pdf&FileName=WPR21LA072%20RoC%20DJensen_Redacted-Rel.pdf - Engine exam report (item 3, PDF, 3 pages, 58 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13194381&FileExtension=pdf&FileName=AFC%20Aircraft%20Works%20Investigation%20N4106K_Redacted-Rel.pdf - Release of aircraft wreckage, NTSB form 6120.15 (item 4, PDF, 1 page, 140 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=13193423&FileExtension=pdf&FileName=Wreckage%20Release_Redacted-Rel.pdf - Video file (item 5, MP4, 29.1 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14254350&FileExtension=mp4&FileName=IMG_5799-Rel.mp4 - Photos FAA (item 6, PDF, 4 pages, 12.4 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=14255767&FileExtension=pdf&FileName=Photos%20(FAA)-Rel.pdf From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.